Rake driving mechanism for sedimentation tanks



' Sept. 14, 1943.

- chH. scoT-r RAKE DRIVING MECHANISQI FOR snmrmumnon TANKS Filed April 25, 1940 Q 4 Sheets-Sha e; l

' ATTORNEY:

INVENTOR.

c. H. SCOTT 2,329,559

Filed April 25, 1940 4 Sheefis-Sheet 2 RAKE DRIVING MECHANISM FOR SEDIMENTATION TANK S VC W m Q\| 1 F C Y B. m 5 \M wh m 1 a n H in 1#\ z u I ,2 m 9 M Q. QM. MN mm m .flm \\\\\k Sept. 14, 1943.-

Sept. 14, 1943. Q. isco-r'r 2,329,559

RAKE DRIVING MECHANISM FOR SEDIMENTATION TANKS Filed April 25, 1940 4 Sheets-Sheet 3 INVENTOR. (l/4M1: $00-77,

ATTORNEY.

c. H. sco'r'r Sept. 14, 1943.

RAKE DRIVING MECHANISM FOR SEDIMENTATION TANK S I Filed April 25, 1940 4 Sheets-Sheet 4 INVENTOIR.

- ATTORNEY than permitting it. y, damaged.

Patented Sept. 14, 1943 j 1:,

I scothhwestport, Conn assignor to The Dorr Company, New York, N; Y'., a corporation of Delaware v This invention relates .to mechanically cleaned sedimentation tanks, and more ,1: specifically, ,to rope-driven, sediment ,wcollecting amechan'ism therefor.

The rope-driven sludge, collectingmeans here in contemplated is of thereciprocating type,"b,eing moved back andiorth inv the tanl-:, to convey the settled matter or sludge to a pointy of;outlet;

, The invention furthermore particularizedq. re lates to improvements inpthe construction and arrangement of the'driving means for thehliope that actuates the sludge collecting means; i

The problem in the operation ofxsuchwa rope drive differs, from other'rope driven taplzaratus, for instance hoists, and rope drivesystems that are substantially vertical, and in whichtheweight of a load lifted and f certain counter'weights tend to take. up or absorb automatically and at all times any-potential slack in the ,rope. Under conditions where thus the rope is automatically sufliciently tensionedto prevent an undesirable slack condition :thereof, there is normally. n0

' danger "of the ropeuwindings ,on-the ropewinding drums. becoming slackand entanglediand'iouled as a result of 'slackness. yConsequent1y,- under those conditions, the rope is'not likelyto get jammed and finally broken due to suchfintanglements. g "j:

Byway o contrast, it should be understood that a problem arises wherean endless rope drive operates in a generally horizontal plane as in the case :where, it actuates a reciprocal sludgecollecte ingdevice in a horizontally extendingsedimentw tion tank. Under such conditionsthe rope may develop a slack which, if unnoticed. or neglected, may lead to disarrangement of thero ewindings on the rope winding drums, andiunless special provisions arev made or precautions taken; such as contemplatedby this invention, therropemay become fouled, jammed, and finallybroken,

It is one object of this invention to provide; an improved rope driving mechanism in which such potential trouble is. minimized or precluded;=-,

These objects are obtained largely ;by constructing and arranging the rope driving;mech'- anism in such a manner that when rope slacknfiss develops, av winding or windings; of the rope,

ratherthan becoming entangledjor j ammed-in-the drive mechanism and doing damage, ,willsimply be allowed to slip off the rope winding or H drums, and thereby to render, the ropeidle-rather and the-:mechanism; to get To this end, a form of anim ietedimgham proposed by this invention ,has a :pair ofirope "winding drums disposed sideby side, -to= rotate about vertical axes, and so arranged with respect to the body ofthe mechanism,thattheropewindQ ing' drums -a redisposed underneaththe drive elements therefor, andso as to be substantially tree from encumbrance s, from below, namely to'the extent that rope windings when slack'may detach themselves-from the drum; to p reve nt damage by entaglement; By the same-token, 't he1; ope windin s may e-r ad y r a pli "tcliesw n drums substantially without-the need of dist s t -m chan s .7

Other objects of the invention are to provide .a drive-unit for therope, which is simple-compact, and efficient withrespect to tractive power, with respect to wear and tea rkonthe drive unit as well as on the rope, and alsoefiicient with respect to positive and-direct driving action on the rope. 'I hese objects are further obtained substantially by the use of a pairof rope-windingdrums, both of which are actively; and directly driven from a-sole source of powen'with' the result that both drums are enabled to assume substantially equal shares oftheload at all times. a g H Other objects have to do withanimproved de sign of the raking means, "L l I ,7

I Some features of theinvention-resideinstructure of a -rake drive mechanism comprisin a pair of rope-driving drums having parallel axesran'd rotatably mounted in a frame or drive gear casing disposed andextending atone side of the diums. This lateral arrangement of theeasing leaves the drums substantially free atfthe other-sidefpermitting ready-application of the rope windings to the drum. When the drum axes. are vertical, and l the gear casing-' is locatedl on top,.th"a'rrange-.

ment readily lends-itself forfincorporation in the for-conveniencebut; they are intended tobe as generic intheir applicationto similar p arts as' the art will permit, ;In;th e accompanying drawings there has ;been illustrated the best embodiment of the invention known tome, but such: embodiment is to be regarded as typical onlyof many possible embodiments, and the invention is not to b -limitedthereto; f ,7 V I s s The novel featuresconsidered characteristic of invention are setforth with particularity in the appended c1aims. 'Ifheinventiom itself-,1 however, both as to its organization and its method of operation, together with additional objects and advantages thereof, will best be understood from the following description of a specific embodiment when read in connection with the accompanying drawings in which:

Fig. 1 is a plan view of a settling tank equipped with a rope drive unit according to this invention.

Fig. 2 is a longitudinal section of the tank shown in Fig. 1, and shown to be provided with raking mechanism comprising a raking element controlled by a parallel link connection.

Fig. 3 is an enlarged detail plan View of the rope drive unit shown in Figs. 1 and 2.

Fig. 4 is a further enlarged partv sectional side View of the unit in Fig. 3.

Fig. 5 is the plan view of amodified construction of a rope drive unit.

Fig. 6 is a relatively enlarged part sectional View of the unit in Fig. 5.

Fig. 7 is a diagrammatic perspective view showing rope windings in crosswise arrangement for driving drums rotating countercurrent to' one an other (corresponding to the construction shown inFigs.5and6).

Fig. 8 is a plan view of the arrangement in Fig. 7, and showing approximately 2'70degrees of the drum engaged by the rope. I

Fig. 9 is a diagrammatic perspective view with rope windings in plain spiral arrangement for driving drums with identical sense of rotation (corresponding to the construction shown in'Figs. 4 and 5).

Fig. 10 is a plan view of the arrangement-in Fig. 9, and showing approximately 180- degrees of the drum engaged by the rope. A

A general view of the present rope-driving mechanism as installed in a mechanically cleaned settling tank, is givenin Figs. 1 and 2. The tank is shown to be of the longitudinal or rectangular type, having a bottom l0, side walls II and |2, an influent end wall I3, and an eilluent end wall l4. The influent is indicated by an inlet opening l5, and the eflluent by an outlet opening IS. A tentative liquid level in thetank is indicated at |6a. A scum launder is shown at IT. Solids that settle on the bottom in the form of sludge are raked to a sump I8 shown to be located at-the inlet end of the tank.

The sludge conveying mechanism has a carriage construction diagrammatically indicated at I9 as having wheels 20, and adapted to travel from end to end of the tank on track rails 2| supported with respect to the side walls oi the tank. Depending from the carriage is the rake construction proper in the way of a parallel link construction, namely, the depending link members 22 and 23, and the rake member 24 shown to have a raking blade 25 at one end andspaced therefrom a similar raking blade 26 at the other end. The link connections 22 and 23 permit raising and lowering of the raking member as between sludgeraking position (shown in full lines) and idle position (shown in dot and dash). A weight 26a and auxiliary rope 21 running over pulley 28 help to raise and lower the rake member 24; The raising and lowering itself of the rake. member may be effected by the main drive rope 29by continued movement of the drive rope, after the-carriage has reached an abutment at the end of the tank. A mechanism for this purpose is shown in the patent to Lund No. 2,101,081. That is to say, when the carriage has reached an abutment at the sludge discharge end of the tank, the pullof the drive rope 25 is continued long enough'to raise the rakin member a suitable distance from the bottom. By suitable means the rake member is then automatically held locked in this position with respect to the carriage. .The rope drive may then be reversed and the carriage returned to the eflluent end of the tank, where the carriage is again stopped and the rake member automatically released from its raised position in a similar manher by the action of the rope drive prior to renewed reversal of the carriage.

The main drive rope 29 is actuated by a rope drive mechanism or unit 30 embodying the main features of this invention, and one modification of which is shown in Figs. 3 and 4.

Considering the special adaptation of thi construction, for the purposes of the sedimentation tank, it will be noted from the side view in Fig. 4 that the drive unit has a pair of rope-driving drums 3| and 32 disposed side by side, each rotatable about a vertical axis. The drums each are shown .to'have .five grooves 3|aand 32a respectively for the-rope windings. The one drum 3| is shown to be disposed at a somewhat higher level than the other drum .32, in orderto compensate at least partly for the so-called fleet angle, thatis, the angle under which the rope from the groove on one drum must otherwise pass to a groove on the other drum.

The drum 3| rotates by way of ball bearings 33 and 34 on a vertical axle 35, the upper end of which is fixedin the hub portion36 of a casing shell 31 as bymeans of nut 31a. The drum 3| has fixed to its upper side a gear 38 as indicated by dowel pins 39 or the like. The gearat its lower side is formed with an annular recess 40 to receive therein annular oil-sealing means as will be described. i 3

The other drum 32 is mounted in the casing shell symmetrically to drum 3| and in a manner identical thereto and hence the showing thereof by way of section is not repeated. However, an anchoring nut 4| fortheaxle of drum:32 will be noted, the corresponding gear for drum 32 being indicated in Fig. 3 by numeral 42., A bridgex 4.3 is provided to connect the lower ends or the two drum axles with one another for stability. 4

Both gears 38 and 42 mesh with a common driving pinion 44 shown to be disposed on the center to center line of'the gears 38 and 42. The pinion 44 is at the free end ofa vertical drive shaft 44a which may be for instance the outlet shaft of a reduction gear motor indicated at 45 and the housing of which is shown to be bolted as at 46 to the topfof the casing shell 31. A bot tom portion 41 or plate is fastened to the casing shell 31 as by screws 48. An opening 49 is provided' in this bottom portion "for the drum 3| and rising from the rim of these openings are annular sealing means 49a lodging 'in'the respective annular recesses 40 of the gears 38- and 42 respec tively, and intended to establish oil-sealing contact with the gears. A similar oil-sealing arrangement is provided in conjunctionwith the other drum 32 and its gear 42, but is not visible in the drawings. The casing has at each end thereof a flange or lug portion 50 and SirespectiVely, by means of which it is shown to be bolted to clips or gusset plates Hand 53 respectively,' which in turn are shown to be fastened as'byTw'elding to supporting beams 54 and 55, respectively. A uide pulley 56 is fastened to the underside of the casing shell by means of abracket 51, the pulley to guide the rope onto or oiT the topmost groove of the drum 3'2. i.

With respect to Fig. 3 and "Fig.4; itzwill be aszasso 3- noted that because of engagement with the com mon driving pinion 44 the gears 38 and 42 rotate in the same sense, that is to say, either. inthe direction of the full line arrows 55a/oro'f the dotted line arrows 5529. Consequently, the drive rope is to be applied to these drums in the man'- ner diagrammatically shown in Fig. 9. That is to say, the'rope is run around both drums in plain spiral fashion so as to form a series of oval loops or-windings (in distinction from the modification in"'Figs. 5, 6' and 7, where the rope windings intersect forming eight-like shapes). Hence it will be neted that the rope windings according to Fig. 4 and Fig. 9 can be applied or removed without disturbing the bridge piece 43.

Inasmuch as both drums 3i and 32. are driven fromasingle source, namely. pinion 44, it will be noted that frictional contact over an arc of approximately 180 of the occupied grooves on each of the drums 3i and 32 transmits tractive power from the drums to the rope. i

The modified unit shown inFigs. and 6 diifers from the unit in Figs. 3 and 4, mainly in that it uses a worm instead of a pinion as the com mon driving element for both rope winding drums, causing the drums to rotate in a sense opposite toone another and necessitating the ro-pe'windr ings to be run crosswise or in figure-eight fashion over the drums. I

The Figs. 5 and 6v modification comprises a gear casing 53 comprising a relativelyshallow ,or pan-shaped body portion 59 having a bottomwall 60 and side wallsfil, and a top or cover portion 62 bolted to the body portion. Again, there is disposed in the casing in substantially symmetrical arrangement a pair of gears, in this instance worm gears 63 and B4, and there are provided a pair of corresponding rope driving drums 65 and 66. Because of'the symmetry only one half of this arrangement need be described. That is to say, the bottom of the gear casing has a downwardly extending hub portion 61 in which rotates a shaft 68 in ball bearings 69 and 10. Fixed upon the upper end ll of the shaft is the Worm gear 63 which is thus wholly enclosed by the gear casing and separated by the casing bottom 60 from the rope winding drum 65 which is fixed to the lower end 12 of the shaft 68.

that the Fig." 6 unit :is provided with-one less means may be providedrfor directing the rope as'desired to or. from. the drive .unit. It is a:feature commonto both-forms of-the invention, that is to say,- according to Fig. '4, as well as according to Fig, 6, that both rope-winding drum are positivelyand simultaneously driven transmit allthe traction.-

Both worm gears 63 and 64 are driven by a common worm l3 interposed between them, the worm being suitably journaled in the gear casing. Consequently the drums 65 and 66 run in opposite directions; that is, either in the direction of the full line arrows 13a or of the dotted line arrows 13b. I

The worm 13 is shown to be driven by Way of reduction gearing M from a motor 15 shown to be mounted on the top or cover portion 62 of the gear casing. A drive rope is applied in crosswise fashion to the rope-driving drums, as indicated at tact in the unit of Fig. 4. Consequently, under normal circumstances there is produced by this unit a traction corresponding to approximately eight times 370. This may be taken to explain from a commondriving element In thisway it is possible to zdistribute thetractive power 'by way of rope friction overboth drums. In other words. achgroove. of a h d um Fakes 9 it share of t e' opdf m t uehw 't tionis realized. Thismeansin terms of; struc; ture that relatively fewer rope I windings are needed thanare required vin cases where one-of the drums is an idler and the otherdrum must This also means that if a p air of rope win ding drums aregeared up withoneanother by way of a common power-driven gear element such as exemplified by the gear 44v in Fig. 4 or. the worm 13 in Fig. 6, lost motion'cancelsfout when the mechanism is}reverse d."' In this way both drums are enabled to assume substantially equal shares of the load at all times. 1 v Furthermorefwith the 'constructionof a ropedrive mechanism herein shown .to be'operatively associated with a"secliment-collectinlg mechanism; the rope winds around the drums in horizontal planes, and thereby may fit itself without the need of substantial directional change into the run of the" drive rope 29 (see Fig. 1).

The operation of the drive 30 (see Figs. 1 and 2) by means of the drive "rope ZS-causes the carriage l9 to travel back andiorth' from end to end of the tank, the forward stroke towards the sludge sump 18 being eifective to convey sludge towards and into the sump since the rake member 24 is then in lowered position, the return stroke away from the sump being idle insofar as the rake member 24 is then raised.

Automatic raising or lowering of the rake member 24 in coordination with the carriage movements may be effected in various ways, one method being described in the patent to Lund No. 2,101,081 above mentioned and outlined.

Features of the invention lie in the parallel link construction including the link member 22 and 23, and the rake member 24. In this connection the arrangement of the two raking blades 25 and 26 is of note, for it makes possible the effective cleansing of the entire tank bottom. The blade 26 cleans out the very rear corner of the tank, and conveys the sludge as far as a point designated by an arrow 16, which is spaced a distance d from the edge of the sump 18. Then, on the next forward stroke of the carriage, the blade 25 will pick up what was previously left at point 16 by the blade 26 and push it over the final distance d into the sump I8.

I claim:

1. In a mechanically cleaned settling tank having a rope driven sediment conveying apparatus in which a substantially horizontally, disposed drive rope actuates a horizontally reoiprocable sediment collecting means, and a self contained power driven rope driving mechanism comprising a horizontally extending frame, gear means mounted in said frame and having a pair of driven gears rotating about vertical parallel axes, a pair of rope driving drums disposed below said gears and also disposed substantially belowsaid frame so as to be laterally and downwardly substantially free of and unencumbered by interfering adjacent structure, each of which drums is concentrically associated with one of said gears so as to rotate therewith, means for driving said gears, which means comprise a motor mounted above said gears and upon said frame and sup ported thereby, and also comprising a gear element driven by said motor and in turn having driving engagement simultaneously with both of said pair of driven gears, said drums being adapted to carry rope windings of said drive rope in substantially horizontal planes, which planes are substantially parallel to the horizontal plane of said drive rope system, said drums further being adapted, because of their unencumbered location below said frame, to permit the unobstructed downward displacement of the rope windings from said drums to take place in case of slackening of the rope, and consequently to permit the rope windings to free themselves from engagement with any active part of the drive mechanism, for obviating the entanglement of the rope on the drive mechanism when the latter continues to operate, and means for marginally supporting said frame at points substantially not lower than the uppermost winding on said drums.

2. Mechanism according to claim 1 in which the frame construction comprises a casingfor said gear means, which casing has marginal lug portions for support.

3. Mechanism according to claim 1 in which a pair of axles is provided, each of which has its upper end portion non-rotatably and axially non-shiitably mounted in said frame, each axle having rotatably mounted on its intermediate portion one of said drums together with the associated gear, and having means provided upon and supported by the lower free end portion for retaining said drum and gear in operating position on said axle. I

4. Mechanism according to claim 1, in which a pair of axles is provided, each axle having its upper end portion non-rotatably and axially nonshiftably mounted on said frame, each axle having rotatably mounted on its intermediate portion one of said drums together with the associated gear, with the addition of a member supported by and fixedly interconnecting the lower free end portions of said axles, for retaining said drums and gears in their respective'operating position upon their axles, said rope windings being disposed in continuous spiral arrangement over both drums, said drive meansbeing effective to rotate both drums in the identical direction.

5. Mechanism according to claim 1, in which a pair of shafts is provided, each shaft having its intermediate portion rotatably mounted in said frame, one of said drums being fixedly mounted upon the lower free end portion of each shaft, and one of said gears being fixedly mounted upon the upper free end portion of each shaft.

6. Mechanism according to claim 1, in which a pair of shafts is provided, each shaft having its intermediate portion rotatably mounted in said frame, one of said drums being fixedly mounted upon the lower free end portion of ,each shaft, one of said gears being fixedly mounted upon the upper free end portion of each shaft, said driving means being effective to rotate said gears in opposite directions, and said rope windings being disposed in crosswise fashion about said drums.

' CHARLES H. SCOTT. 

